C# 实现IAccessible学习（二）

第一个示例

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新建项目，添加引用：

代码：

using System;using System.Text;using System.Windows.Forms;using System.Runtime.InteropServices;using System.Globalization;using System.Reflection;namespace TryQq{    /// <summary>    /// Interface definition for Excel.Window interface    /// </summary>    [Guid("00020893-0000-0000-C000-000000000046")]    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]    public interface ExcelWindow    {    }    /// <summary>    /// This class is needed as a workaround to http://support.microsoft.com/default.aspx?scid=kb;en-us;320369    /// Excel automation will fail with the follwoing error on systems with non-English regional settings:    /// "Old format or invalid type library. (Exception from HRESULT: 0x80028018 (TYPE_E_INVDATAREAD))"     /// </summary>    class UILanguageHelper : IDisposable    {        private CultureInfo _currentCulture;        public UILanguageHelper()        {            // save current culture and set culture to en-US             _currentCulture = System.Threading.Thread.CurrentThread.CurrentCulture;            System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");        }        public void Dispose()        {            // reset to original culture             System.Threading.Thread.CurrentThread.CurrentCulture = _currentCulture;        }    }    public partial class Form1 : Form    {        [DllImport("user32.dll", SetLastError = true)]        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);        [DllImport("Oleacc.dll")]        static extern int AccessibleObjectFromWindow(int hwnd, uint dwObjectID, byte[] riid, out ExcelWindow ptr);        public delegate bool EnumChildCallback(int hwnd, ref int lParam);        [DllImport("User32.dll")]        public static extern bool EnumChildWindows(int hWndParent, EnumChildCallback lpEnumFunc, ref int lParam);        [DllImport("User32.dll")]        public static extern int GetClassName(int hWnd, StringBuilder lpClassName, int nMaxCount);        public static bool EnumChildProc(int hwndChild, ref int lParam)        {            StringBuilder buf = new StringBuilder(128);            GetClassName(hwndChild, buf, 128);            if (buf.ToString() == "EXCEL7")            {                lParam = hwndChild;                return false;            }            return true;        }        public Form1()        {            InitializeComponent();            // Use the window class name ("XLMAIN") to retrieve a handle to Excel's main window.            // Alternatively you can get the window handle via the process id:            // int hwnd = (int)Process.GetProcessById(excelPid).MainWindowHandle;            //            int hwnd = (int)FindWindow("XLMAIN", null);            if (hwnd != 0)            {                int hwndChild = 0;                // Search the accessible child window (it has class name "EXCEL7")                 EnumChildCallback cb = new EnumChildCallback(EnumChildProc);                EnumChildWindows(hwnd, cb, ref hwndChild);                if (hwndChild != 0)                {                    // We call AccessibleObjectFromWindow, passing the constant OBJID_NATIVEOM (defined in winuser.h)                     // and IID_IDispatch - we want an IDispatch pointer into the native object model.                    //                    const uint OBJID_NATIVEOM = 0xFFFFFFF0;                    Guid IID_IDispatch = new Guid("{00020400-0000-0000-C000-000000000046}");                    ExcelWindow ptr;                    int hr = AccessibleObjectFromWindow(hwndChild, OBJID_NATIVEOM, IID_IDispatch.ToByteArray(), out ptr);                    if (hr >= 0)                    {                        // We successfully got a native OM IDispatch pointer, we can QI this for                        // an Excel Application using reflection (and using UILanguageHelper to                         // fix http://support.microsoft.com/default.aspx?scid=kb;en-us;320369)                        //                        using (UILanguageHelper fix = new UILanguageHelper())                        {                            object xlApp = ptr.GetType().InvokeMember("Application", BindingFlags.GetProperty, null, ptr, null);                            object version = xlApp.GetType().InvokeMember("Version", BindingFlags.GetField | BindingFlags.InvokeMethod | BindingFlags.GetProperty, null, xlApp, null);                            Console.WriteLine(string.Format("Excel version is: {0}", version));                        }                    }                }            }        }    }}

这个winform程序可以输出excel版本号。
当中AccessibleObjectFromWindow用法还没有搞明白。